A set of standard blood tests is recommended for all women at the start of their pregnancy care. Colloquially, we call these the “booking” blood tests. Your GP will usually arrange the tests in readiness for your first visit to the obstetrician. Each test has been chosen because it will identify a problem that can impact your pregnancy. These tests are an important step in setting you up for a healthy pregnancy.
Last year, North Shore Private Hospital asked me to give a talk to local GPs on the latest guidelines for pregnancy tests. I thought this information would be really interesting to the women who are actually having the tests! So I’ve adapted the notes from my GP talk and summarized the booking bloods for you below.
Booking tests recommended for all pregnant women:
- Full blood count. We mostly do this test to check for anaemia. The most common cause of anemia is being low in iron, but there are other causes. We also check your platelets – these are the cells responsible for blood clotting. Too many or too few platelets is a problem.
- Blood group and antibody screen. We check if your blood type is “Rhesus positive” or “Rhesus negative.” Rhesus negative women sometimes make an antibody that attacks the unborn baby’s blood cells. To prevent this, we give all Rhesus negative women an injection called Anti-D. The blood group test can also pick up rare antibodies, which need special management.
- Hepatitis B. A virus that affects the liver. It’s more common than people realise. We have ways to reduce the chance of mum passing it to baby.
- Hepatitis C. Another virus that affects the liver. It’s important to identify infected women and get them into treatment, because Hepatitis C has serious long-term health implications.
- HIV. This is the virus that can lead to AIDS. With modern management, we can significantly reduce the chance of mum passing the virus to baby. We can also significantly improve mum’s health.
- Rubella (German measles). Catching German measles while pregnant can cause serious harm to your unborn baby. We need to identify mums with no immunity, in case there is an outbreak. We also offer vaccination to these mums after baby is born.
- Syphilis. Syphilis is a bacterial infection. Ithas beenrare for decades, but it’s making a comeback. It can lead to stillbirth, brain damage and death in the newborn. For mums, untreated syphilis can attack many different organs, causing serious illness or death.
- Urine sample. Some women have bacteria in their urine without knowing it. Treating the bacteria reduces the risk of developing a serious kidney infection.
- Cervical screening. We used to call this a Pap smear – the collection process is the same, although what we do in the lab is a little different these days. We can (and should) do cervical screening for any woman who would normally be due in the course of her pregnancy. There is no evidence that a cervical smear causes any harm during pregnancy.
Extra tests recommended for women with special risk factors:
- Thyroid test. The thyroid is a gland in your neck that affects your metabolism and several other important body processes. Some women have a higher chance of developing thyroid problems. Both overactive and underactive thyroids can cause pregnancy complications. We will test your thyroid if you fall into the “at risk” group.
- Early diabetes screening. Again, some women are at higher risk of either undiagnosed Type 2 diabetes, or early onset gestational diabetes. Both benefit from active management by a multi-disciplinary team. We’ll screen high-risk patients early in pregnancy and all patients at around 28 weeks.
- Thalassemia. This is a type of inherited anaemia. You might know it runs in your family or be from an area where thalassemia is common. Sometimes we see a change on your full blood count. In these cases we can order specialized testing.
- Varicella. This is the fancy name for the chickenpox virus. If you aren’t sure you had chickenpox as a kid, we’ll test to see if you have immunity. Women who aren’t immune and who come in contact with chickenpox need to notify their obstetrician immediately. Like many other viruses, chickenpox can infect babies in the womb and cause fetal abnormalities.
- Chlamydia. This is a really common STI; a lot of people are infected without knowing. The good news is it’s simple to diagnose and treat.
- Vitamin D. Vitamin D has a few jobs, but it’s mainly important for the development of bones and tooth enamel. For a while there was a fad for testing every pregnant woman’s Vitamin D level. We now only recommend testing women who are at high risk of Vitamin D deficiency.